Renal pathology 2

Question 1

What is acute kidney injury?

Answer 1

This is when the kidney fails over a short time and is characterised by a rapid fall in glomerular filtration rate (GFR) and an increase in creatine and urea levels. It may be reversible.

Question 2

What are the three subdivisions of AKI?

Answer 2

• Prerenal
• Intrinsic
• Postrenal

Question 3

Prerenal causes of AKI

Answer 3

• Hypovolaemia
  
  • Haemorrhage
  • Burns
  • Diuretic use
• Shock
  
  • Sepsis
  • Cardiogenic
• Hypoperfusion
  
  • Hepatorenal syndrome
  • NSAID use
  • ACE inhibitor use
• Odematous conditions
  
  • Heart failure
  • Nephrotic syndrome

Question 4

Intrinsic causes of AKI

Answer 4

• Glomerular disease
  
  • Glomerulonephritis
  • Vasculitis
  • Immune complex disease eg, systemic lupus erythmatosus
• Vascular lesions
  
  • Bilateral renal artery stenosis
  • Microangiopathy
  • Malignant hypertension
• Tubulointerstitial disease
  
  • Acute tubular necrosis
  • Acute tubulointerstitial nephritis
  • Multiple myeloma
  • Nephrotoxic drugs

Question 5

Postrenal causes of AKI

Answer 5

• Obstruction of the ureter
  
  • Stones
  • Tumour
• Obstruction of the bladder neck
  
  • Stones
  • Tumour
  • Benign prostatic hypertrophy
  • Prostate cancer
• Obstuction of the urethra
  
  • Tumour
  • Stricture

Question 6

Signs and symptoms of acute kidney injury

Answer 6

• Oligouria/anuria
• Nausea and vomiting
• Confusion
• Hypertension
• Abdominal/flank pain
• Signs of fluid overload eg ↑ jugular venous pressure (JVP)

Question 7

Investigations for acute kidney injury

Answer 7

• GFR
• Bloods
  
  • FBC and platelets, U&Es, creatinine, calcium and phosphate levels, ESR, CRP, immunology, virology
• Urinalysis
  
  • blood, protein, glucose, leucocytes and nitrates, Bence Jones protein
• Imaging
  
  • ultrasound scan

Question 8

Treatment of acute kidney injury

Answer 8

• Maintain renal blood flow and fluid balance
• Monitor electrolytes
• Treat underying cause
• Stop all nephrotoxic drugs

Question 9

Complications of acute kidney injury

Answer 9

• Metabolic acidosis
• Hyperkalaemia
• Hyperphosphataemia
• Pulmonary oedema

Question 10

What is chronic kidney injury?

Answer 10

This is well established renal impairment and is irreversible. Renal function progressively worsens with time. Without treatment the patient will eventually develop end-stage kidney disease (ESKD).

Question 11

Causes of chronic kidney injury

Answer 11

• any renal disease
• glomerulonephritis
• hypertension
• diabetes mellitus
• malignancy
• anatomical abnormalities of the renal tract
• herediatary disase eg polycystic renal disease

Question 12

Signs and symptoms of chronic kidney disease

Answer 12

• oligouria/anuria/polyuria
• nausea and vomiting
• confusion
• hypertension
• oedema (peripheral and pulmonary)
• fatigue
• metallic taste in mouth
• unintentional weight loss
• itchy skin
• skin pigmentation
• Kaussmaul breathing (metabolic acidosis)
• anaemia

Question 13

Investigations for chronic kidney injury

Answer 13

• GFR
• Bloods
  
  • FBC, U&Es, creatinine, calcium and phosphate levles, ESR, CRP, immunology, virology
• Urinalysis
  
  • blood, protein, glucose, leucocytes and nitrates, Bence Jones proteinuria (multple myeloma)
• Imaging
  
  • Ultrasound scan
• Renal biopsy

Question 14

Treatmtent for chronic kidney injury

Answer 14

• Medical
  
  • treat underlying cause and complications
  • control blood pressure
  • treat anaemia
  • treat acidosis (with sodium bicarbonate)
  • treat hyperphosphataemia (with phosphate binders)
• Surgical
  
  • dialysis (haemodialysis or peritoneal dialysis)
  • renal transplantation